Pregnancy loss and autoantibodies against phospholipid-binding proteins

To evaluate the relationship between antibodies against β2-glycoprotein I or prothrombin and pregnancy losses in women with antiphospholipid antibodies. Women with antiphospholipid antibodies, (lupus anticoagulant and/or anticardiolipin antibodies), with (n = 41) and without (n = 61) a history of pregnancy loss were evaluated. Thirty-one out of the forty-one patients with pregnancy loss had early miscarriages (at less than 13 weeks) and ten patients had late miscarriages. Immunoglobulin (Ig)-G and IgM anti-β2-glycoprotein I and anti-prothrombin antibodies were measured by an enzyme-linked immunosorbent assay method. A significant association between pregnancy loss and positive IgM anti-β2-glycoprotein I antibodies was found (odds ratio 2.6; 95% confidence interval 1.03, 6.6; P = .043). Women with late pregnancy loss had higher levels of both IgG and IgM anti-β2-glycoprotein I antibodies compared with controls (P < .05). There was a good correlation between anticardiolipin and anti-β2-glycoprotein I antibodies levels (IgG: r = 0.75; IgM: r = 0.73). In contrast, there was no correlation between the levels of anticardiolipin or antiβ2-glycoprotein I antibodies and the levels of anti-prothrombin antibodies. Furthermore, the presence of antiprothrombin antibodies was not associated with a history of pregnancy loss. The result of our study shows that there is a relationship between the presence of IgM anti-β2-glycoprotein I and previous miscarriages in women with antiphospholipid antibodies.